A role for calcium in gonadotrophin-releasing hormone (GnRH) stimulated secretion of chorionic gonadotrophin by first trimester human placental minces in vitro |
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Authors: | N Mathialagan A J Rao |
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Affiliation: | Department of Biochemistry, Indian Institute of Science, Bangalore. |
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Abstract: | In vitro studies using first-trimester human placental minces have shown that stimulation of human chorionic gonadotrophin (hCG) secretion by gonadotrophin-releasing hormone (GnRH) is dependent upon the presence of extracellular calcium. Addition of GnRH to first-trimester placental minces in vitro was found to stimulate 45Ca2+ uptake into placental minces, and the process was associated with an increase in immunoreactive hCG in the medium. Addition of GnRH to placental minces preloaded with 45Ca2+ stimulated the efflux of 45Ca2+ within one minute. The calmodulin inhibitors chlorpromazine and trifluoperazine inhibited the basal uptake and efflux of 45Ca2+, suggesting the involvement of calmodulin in the mobilization of calcium in the placenta. |
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